ICU 69.1: icu::Transliterator Class Reference

ICU 69.1 69.1

Data Structures | Public Types | Public Member Functions | Static Public Member Functions | Protected Member Functions | Static Protected Member Functions | Friends
icu::Transliterator Class Referenceabstract

`Transliterator` is an abstract class that transliterates text from one format to another. More...

`#include <translit.h>`

Inheritance diagram for icu::Transliterator:

## Data Structures
union | Token
| A context integer or pointer for a factory function, passed by value. More...

## Public Types
typedef Transliterator *(* | Factory) (const UnicodeString &ID, Token context)
| A function that creates and returns a Transliterator. More...

## Public Member Functions
virtual | ~Transliterator ()
| Destructor. More...
virtual Transliterator * | clone () const
| Implements Cloneable. More...
virtual int32_t | transliterate (Replaceable &text, int32_t start, int32_t limit) const
| Transliterates a segment of a string, with optional filtering. More...
virtual void | transliterate (Replaceable &text) const
| Transliterates an entire string in place. More...
virtual void | transliterate (Replaceable &text, UTransPosition &index, const UnicodeString &insertion, UErrorCode &status) const
| Transliterates the portion of the text buffer that can be transliterated unambiguosly after new text has been inserted, typically as a result of a keyboard event. More...
virtual void | transliterate (Replaceable &text, UTransPosition &index, UChar32 insertion, UErrorCode &status) const
| Transliterates the portion of the text buffer that can be transliterated unambiguosly after a new character has been inserted, typically as a result of a keyboard event. More...
virtual void | transliterate (Replaceable &text, UTransPosition &index, UErrorCode &status) const
| Transliterates the portion of the text buffer that can be transliterated unambiguosly. More...
virtual void | finishTransliteration (Replaceable &text, UTransPosition &index) const
| Finishes any pending transliterations that were waiting for more characters. More...
virtual void | filteredTransliterate (Replaceable &text, UTransPosition &index, UBool incremental) const
| Transliterate a substring of text, as specified by index, taking filters into account. More...
int32_t | getMaximumContextLength (void) const
| Returns the length of the longest context required by this transliterator. More...
virtual const UnicodeString & | getID (void) const
| Returns a programmatic identifier for this transliterator. More...
const UnicodeFilter * | getFilter (void) const
| Returns the filter used by this transliterator, or `NULL` if this transliterator uses no filter. More...
UnicodeFilter * | orphanFilter (void)
| Returns the filter used by this transliterator, or `NULL` if this transliterator uses no filter. More...
void | adoptFilter (UnicodeFilter *adoptedFilter)
| Changes the filter used by this transliterator. More...
Transliterator * | createInverse (UErrorCode &status) const
| Returns this transliterator's inverse. More...
virtual UnicodeString & | toRules (UnicodeString &result, UBool escapeUnprintable) const
| Create a rule string that can be passed to createFromRules() to recreate this transliterator. More...
int32_t | countElements () const
| Return the number of elements that make up this transliterator. More...
const Transliterator & | getElement (int32_t index, UErrorCode &ec) const
| Return an element that makes up this transliterator. More...
UnicodeSet & | getSourceSet (UnicodeSet &result) const
| Returns the set of all characters that may be modified in the input text by this Transliterator. More...
virtual void | handleGetSourceSet (UnicodeSet &result) const
| Framework method that returns the set of all characters that may be modified in the input text by this Transliterator, ignoring the effect of this object's filter. More...
virtual UnicodeSet & | getTargetSet (UnicodeSet &result) const
| Returns the set of all characters that may be generated as replacement text by this transliterator. More...
virtual UClassID | getDynamicClassID (void) const =0
| Returns a unique class ID polymorphically. More...
Public Member Functions inherited from icu::UObject
virtual | ~UObject ()
| Destructor. More...

## Static Public Member Functions
static Token | integerToken (int32_t)
| Return a token containing an integer. More...
static Token | pointerToken (void *)
| Return a token containing a pointer. More...
static UnicodeString & | getDisplayName (const UnicodeString &ID, UnicodeString &result)
| Returns a name for this transliterator that is appropriate for display to the user in the default locale. More...
static UnicodeString & | getDisplayName (const UnicodeString &ID, const Locale &inLocale, UnicodeString &result)
| Returns a name for this transliterator that is appropriate for display to the user in the given locale. More...
static Transliterator * | createInstance (const UnicodeString &ID, UTransDirection dir, UParseError &parseError, UErrorCode &status)
| Returns a `Transliterator` object given its ID. More...
static Transliterator * | createInstance (const UnicodeString &ID, UTransDirection dir, UErrorCode &status)
| Returns a `Transliterator` object given its ID. More...
static Transliterator * | createFromRules (const UnicodeString &ID, const UnicodeString &rules, UTransDirection dir, UParseError &parseError, UErrorCode &status)
| Returns a `Transliterator` object constructed from the given rule string. More...
static void | registerFactory (const UnicodeString &id, Factory factory, Token context)
| Registers a factory function that creates transliterators of a given ID. More...
static void | registerInstance (Transliterator *adoptedObj)
| Registers an instance `obj` of a subclass of `Transliterator` with the system. More...
static void | registerAlias (const UnicodeString &aliasID, const UnicodeString &realID)
| Registers an ID string as an alias of another ID string. More...
static void | unregister (const UnicodeString &ID)
| Unregisters a transliterator or class. More...
static StringEnumeration * | getAvailableIDs (UErrorCode &ec)
| Return a StringEnumeration over the IDs available at the time of the call, including user-registered IDs. More...
static int32_t | countAvailableSources (void)
| Return the number of registered source specifiers. More...
static UnicodeString & | getAvailableSource (int32_t index, UnicodeString &result)
| Return a registered source specifier. More...
static int32_t | countAvailableTargets (const UnicodeString &source)
| Return the number of registered target specifiers for a given source specifier. More...
static UnicodeString & | getAvailableTarget (int32_t index, const UnicodeString &source, UnicodeString &result)
| Return a registered target specifier for a given source. More...
static int32_t | countAvailableVariants (const UnicodeString &source, const UnicodeString &target)
| Return the number of registered variant specifiers for a given source-target pair. More...
static UnicodeString & | getAvailableVariant (int32_t index, const UnicodeString &source, const UnicodeString &target, UnicodeString &result)
| Return a registered variant specifier for a given source-target pair. More...
static UClassID | getStaticClassID (void)
| Return the class ID for this class. More...
static int32_t | countAvailableIDs (void)
| Return the number of IDs currently registered with the system. More...
static const UnicodeString & | getAvailableID (int32_t index)
| Return the index-th available ID. More...

## Protected Member Functions
| Transliterator (const UnicodeString &ID, UnicodeFilter *adoptedFilter)
| Default constructor. More...
| Transliterator (const Transliterator &)
| Copy constructor. More...
Transliterator & | operator= (const Transliterator &)
| Assignment operator. More...
virtual void | handleTransliterate (Replaceable &text, UTransPosition &pos, UBool incremental) const =0
| Abstract method that concrete subclasses define to implement their transliteration algorithm. More...
void | setMaximumContextLength (int32_t maxContextLength)
| Method for subclasses to use to set the maximum context length. More...
void | setID (const UnicodeString &id)
| Set the ID of this transliterators. More...

## Static Protected Member Functions
static Transliterator * | createBasicInstance (const UnicodeString &id, const UnicodeString *canon)
| Create a transliterator from a basic ID. More...
static void | _registerFactory (const UnicodeString &id, Factory factory, Token context)
static void | _registerInstance (Transliterator *adoptedObj)
static void | _registerAlias (const UnicodeString &aliasID, const UnicodeString &realID)
static void | _registerSpecialInverse (const UnicodeString &target, const UnicodeString &inverseTarget, UBool bidirectional)
| Register two targets as being inverses of one another. More...
static int32_t | _countAvailableSources (void)
| Non-mutexed internal method. More...
static UnicodeString & | _getAvailableSource (int32_t index, UnicodeString &result)
| Non-mutexed internal method. More...
static int32_t | _countAvailableTargets (const UnicodeString &source)
| Non-mutexed internal method. More...
static UnicodeString & | _getAvailableTarget (int32_t index, const UnicodeString &source, UnicodeString &result)
| Non-mutexed internal method. More...
static int32_t | _countAvailableVariants (const UnicodeString &source, const UnicodeString &target)
| Non-mutexed internal method. More...
static UnicodeString & | _getAvailableVariant (int32_t index, const UnicodeString &source, const UnicodeString &target, UnicodeString &result)
| Non-mutexed internal method. More...

## Friends
class | TransliteratorParser
class | TransliteratorIDParser
class | TransliteratorAlias

## Detailed Description

`Transliterator` is an abstract class that transliterates text from one format to another.

The most common kind of transliterator is a script, or alphabet, transliterator. For example, a Russian to Latin transliterator changes Russian text written in Cyrillic characters to phonetically equivalent Latin characters. It does not translate Russian to English! Transliteration, unlike translation, operates on characters, without reference to the meanings of words and sentences.

Although script conversion is its most common use, a transliterator can actually perform a more general class of tasks. In fact, `Transliterator` defines a very general API which specifies only that a segment of the input text is replaced by new text. The particulars of this conversion are determined entirely by subclasses of `Transliterator`.

Transliterators are stateless

`Transliterator` objects are stateless; they retain no information between calls to `transliterate()`. (However, this does not mean that threads may share transliterators without synchronizing them. Transliterators are not immutable, so they must be synchronized when shared between threads.) This might seem to limit the complexity of the transliteration operation. In practice, subclasses perform complex transliterations by delaying the replacement of text until it is known that no other replacements are possible. In other words, although the `Transliterator` objects are stateless, the source text itself embodies all the needed information, and delayed operation allows arbitrary complexity.

Batch transliteration

The simplest way to perform transliteration is all at once, on a string of existing text. This is referred to as batch transliteration. For example, given a string `input` and a transliterator `t`, the call

    String result = t.transliterate(input);

will transliterate it and return the result. Other methods allow the client to specify a substring to be transliterated and to use Replaceable objects instead of strings, in order to preserve out-of-band information (such as text styles).

Keyboard transliteration

Somewhat more involved is keyboard, or incremental transliteration. This is the transliteration of text that is arriving from some source (typically the user's keyboard) one character at a time, or in some other piecemeal fashion.

In keyboard transliteration, a `Replaceable` buffer stores the text. As text is inserted, as much as possible is transliterated on the fly. This means a GUI that displays the contents of the buffer may show text being modified as each new character arrives.

Consider the simple rule-based Transliterator:

        th>{theta}
        t>{tau}

When the user types 't', nothing will happen, since the transliterator is waiting to see if the next character is 'h'. To remedy this, we introduce the notion of a cursor, marked by a '|' in the output string:

        t>|{tau}
        {tau}h>{theta}

Now when the user types 't', tau appears, and if the next character is 'h', the tau changes to a theta. This is accomplished by maintaining a cursor position (independent of the insertion point, and invisible in the GUI) across calls to `transliterate()`. Typically, the cursor will be coincident with the insertion point, but in a case like the one above, it will precede the insertion point.

Keyboard transliteration methods maintain a set of three indices that are updated with each call to `transliterate()`, including the cursor, start, and limit. Since these indices are changed by the method, they are passed in an `int[]` array. The `START` index marks the beginning of the substring that the transliterator will look at. It is advanced as text becomes committed (but it is not the committed index; that's the `CURSOR`). The `CURSOR` index, described above, marks the point at which the transliterator last stopped, either because it reached the end, or because it required more characters to disambiguate between possible inputs. The `CURSOR` can also be explicitly set by rules in a rule-based Transliterator. Any characters before the `CURSOR` index are frozen; future keyboard transliteration calls within this input sequence will not change them. New text is inserted at the `LIMIT` index, which marks the end of the substring that the transliterator looks at.

Because keyboard transliteration assumes that more characters are to arrive, it is conservative in its operation. It only transliterates when it can do so unambiguously. Otherwise it waits for more characters to arrive. When the client code knows that no more characters are forthcoming, perhaps because the user has performed some input termination operation, then it should call `finishTransliteration()` to complete any pending transliterations.

Inverses

Pairs of transliterators may be inverses of one another. For example, if transliterator A transliterates characters by incrementing their Unicode value (so "abc" -> "def"), and transliterator B decrements character values, then A is an inverse of B and vice versa. If we compose A with B in a compound transliterator, the result is the indentity transliterator, that is, a transliterator that does not change its input text.

The `Transliterator` method `getInverse()` returns a transliterator's inverse, if one exists, or `null` otherwise. However, the result of `getInverse()` usually will not be a true mathematical inverse. This is because true inverse transliterators are difficult to formulate. For example, consider two transliterators: AB, which transliterates the character 'A' to 'B', and BA, which transliterates 'B' to 'A'. It might seem that these are exact inverses, since

> "A" x AB -> "B"
> "B" x BA -> "A"

where 'x' represents transliteration. However,

> "ABCD" x AB -> "BBCD"
> "BBCD" x BA -> "AACD"

so AB composed with BA is not the identity. Nonetheless, BA may be usefully considered to be AB's inverse, and it is on this basis that AB`.getInverse()` could legitimately return BA.

IDs and display names

A transliterator is designated by a short identifier string or ID. IDs follow the format source-destination, where source describes the entity being replaced, and destination describes the entity replacing source. The entities may be the names of scripts, particular sequences of characters, or whatever else it is that the transliterator converts to or from. For example, a transliterator from Russian to Latin might be named "Russian-Latin". A transliterator from keyboard escape sequences to Latin-1 characters might be named "KeyboardEscape-Latin1". By convention, system entity names are in English, with the initial letters of words capitalized; user entity names may follow any format so long as they do not contain dashes.

In addition to programmatic IDs, transliterator objects have display names for presentation in user interfaces, returned by getDisplayName.

Factory methods and registration

In general, client code should use the factory method createInstance to obtain an instance of a transliterator given its ID. Valid IDs may be enumerated using `getAvailableIDs()`. Since transliterators are mutable, multiple calls to createInstance with the same ID will return distinct objects.

In addition to the system transliterators registered at startup, user transliterators may be registered by calling `registerInstance()` at run time. A registered instance acts a template; future calls to createInstance with the ID of the registered object return clones of that object. Thus any object passed to `registerInstance()` must implement `clone()` propertly. To register a transliterator subclass without instantiating it (until it is needed), users may call registerFactory. In this case, the objects are instantiated by invoking the zero-argument public constructor of the class.

Subclassing

Subclasses must implement the abstract method `handleTransliterate()`.

Subclasses should override the `transliterate()` method taking a `Replaceable` and the `transliterate()` method taking a `String` and `StringBuffer` if the performance of these methods can be improved over the performance obtained by the default implementations in this class.

Rule syntax

A set of rules determines how to perform translations. Rules within a rule set are separated by semicolons (';'). To include a literal semicolon, prefix it with a backslash ('\'). Unicode Pattern_White_Space is ignored. If the first non-blank character on a line is '#', the entire line is ignored as a comment.

Each set of rules consists of two groups, one forward, and one reverse. This is a convention that is not enforced; rules for one direction may be omitted, with the result that translations in that direction will not modify the source text. In addition, bidirectional forward-reverse rules may be specified for symmetrical transformations.

Note: Another description of the Transliterator rule syntax is available in section Transform Rules Syntax of UTS #35: Unicode LDML. The rules are shown there using arrow symbols ← and → and ↔. ICU supports both those and the equivalent ASCII symbols < and > and <>.

Rule statements take one of the following forms:

`$alefmadda=\u0622;`
  Variable definition. The name on the left is assigned the text on the right. In this example, after this statement, instances of the left hand name, "`$alefmadda`", will be replaced by the Unicode character U+0622. Variable names must begin with a letter and consist only of letters, digits, and underscores. Case is significant. Duplicate names cause an exception to be thrown, that is, variables cannot be redefined. The right hand side may contain well-formed text of any length, including no text at all ("`$empty=;`"). The right hand side may contain embedded `UnicodeSet` patterns, for example, "`$softvowel=[eiyEIY]`".
`ai>$alefmadda;`
  Forward translation rule. This rule states that the string on the left will be changed to the string on the right when performing forward transliteration.
`ai<$alefmadda;`
  Reverse translation rule. This rule states that the string on the right will be changed to the string on the left when performing reverse transliteration.

`ai<>$alefmadda;`
  Bidirectional translation rule. This rule states that the string on the right will be changed to the string on the left when performing forward transliteration, and vice versa when performing reverse transliteration.

Translation rules consist of a match pattern and an output string. The match pattern consists of literal characters, optionally preceded by context, and optionally followed by context. Context characters, like literal pattern characters, must be matched in the text being transliterated. However, unlike literal pattern characters, they are not replaced by the output text. For example, the pattern "`abc{def}`" indicates the characters "`def`" must be preceded by "`abc`" for a successful match. If there is a successful match, "`def`" will be replaced, but not "`abc`". The final '`}`' is optional, so "`abc{def`" is equivalent to "`abc{def}`". Another example is "`{123}456`" (or "`123}456`") in which the literal pattern "`123`" must be followed by "`456`".

The output string of a forward or reverse rule consists of characters to replace the literal pattern characters. If the output string contains the character '`|`', this is taken to indicate the location of the cursor after replacement. The cursor is the point in the text at which the next replacement, if any, will be applied. The cursor is usually placed within the replacement text; however, it can actually be placed into the precending or following context by using the special character '@'. Examples:

        a {foo} z > | @ bar; # foo -> bar, move cursor before a
        {foo} xyz > bar @|; # foo -> bar, cursor between y and z

UnicodeSet

`UnicodeSet` patterns may appear anywhere that makes sense. They may appear in variable definitions. Contrariwise, `UnicodeSet` patterns may themselves contain variable references, such as "`$a=[a-z];$not_a=[^$a]`", or "`$range=a-z;$ll=[$range]`".

`UnicodeSet` patterns may also be embedded directly into rule strings. Thus, the following two rules are equivalent:

        $vowel=[aeiou]; $vowel>'*'; # One way to do this
        [aeiou]>'*'; # Another way

See UnicodeSet for more documentation and examples.

Segments

Segments of the input string can be matched and copied to the output string. This makes certain sets of rules simpler and more general, and makes reordering possible. For example:

        ([a-z]) > $1 $1; # double lowercase letters
        ([:Lu:]) ([:Ll:]) > $2 $1; # reverse order of Lu-Ll pairs

The segment of the input string to be copied is delimited by "`(`" and "`)`". Up to nine segments may be defined. Segments may not overlap. In the output string, "`$1`" through "`$9`" represent the input string segments, in left-to-right order of definition.

Anchors

Patterns can be anchored to the beginning or the end of the text. This is done with the special characters '`^`' and '`$`'. For example:

      ^ a   > 'BEG_A';   # match 'a' at start of text
        a   > 'A'; # match other instances of 'a'
        z $ > 'END_Z';   # match 'z' at end of text
        z   > 'Z';       # match other instances of 'z'

It is also possible to match the beginning or the end of the text using a `UnicodeSet`. This is done by including a virtual anchor character '`$`' at the end of the set pattern. Although this is usually the match character for the end anchor, the set will match either the beginning or the end of the text, depending on its placement. For example:

      $x = [a-z$];   # match 'a' through 'z' OR anchor
      $x 1    > 2;   # match '1' after a-z or at the start
         3 $x > 4;   # match '3' before a-z or at the end

Example

The following example rules illustrate many of the features of the rule language.

Rule 1. | `abc{def}>x|y`
Rule 2. | `xyz>r`
Rule 3. | `yz>q`

Applying these rules to the string "`adefabcdefz`" yields the following results:

`|adefabcdefz` | Initial state, no rules match. Advance cursor.
`a|defabcdefz` | Still no match. Rule 1 does not match because the preceding context is not present.
`ad|efabcdefz` | Still no match. Keep advancing until there is a match...
`ade|fabcdefz` | ...
`adef|abcdefz` | ...
`adefa|bcdefz` | ...
`adefab|cdefz` | ...
`adefabc|defz` | Rule 1 matches; replace "`def`" with "`xy`" and back up the cursor to before the '`y`'.
`adefabcx|yz` | Although "`xyz`" is present, rule 2 does not match because the cursor is before the '`y`', not before the '`x`'. Rule 3 does match. Replace "`yz`" with "`q`".
`adefabcxq|` | The cursor is at the end; transliteration is complete.

The order of rules is significant. If multiple rules may match at some point, the first matching rule is applied.

Forward and reverse rules may have an empty output string. Otherwise, an empty left or right hand side of any statement is a syntax error.

Single quotes are used to quote any character other than a digit or letter. To specify a single quote itself, inside or outside of quotes, use two single quotes in a row. For example, the rule "`'>'>o''clock`" changes the string "`>`" to the string "`o'clock`".

Notes

While a Transliterator is being built from rules, it checks that the rules are added in proper order. For example, if the rule "a>x" is followed by the rule "ab>y", then the second rule will throw an exception. The reason is that the second rule can never be triggered, since the first rule always matches anything it matches. In other words, the first rule masks the second rule.

Author
  Alan Liu

Stable:
  ICU 2.0

Definition at line 490 of file translit.h.

## Member Typedef Documentation

## ◆ Factory

typedef Transliterator*( * icu::Transliterator::Factory) (const UnicodeString &ID, Token context)

A function that creates and returns a Transliterator.

When invoked, it will be passed the ID string that is being instantiated, together with the context pointer that was passed in when the factory function was first registered. Many factory functions will ignore both parameters, however, functions that are registered to more than one ID may use the ID or the context parameter to parameterize the transliterator they create.

Parameters

  ID | the string identifier for this transliterator
  context | a context pointer that will be stored and later passed to the factory function when an ID matching the registration ID is being instantiated with this factory.

Stable:
  ICU 2.4

Definition at line 560 of file translit.h.

## Constructor & Destructor Documentation

## ◆ Transliterator() [1/2]

icu::Transliterator::Transliterator | ( | const UnicodeString & | ID,
|  | UnicodeFilter * | adoptedFilter
| ) |  |
| protected

Default constructor.

Parameters

  ID | the string identifier for this transliterator
  adoptedFilter | the filter. Any character for which `filter.contains()` returns `false` will not be altered by this transliterator. If `filter` is `null` then no filtering is applied.

Stable:
  ICU 2.4

## ◆ Transliterator() [2/2]

icu::Transliterator::Transliterator | ( | const Transliterator & |  | ) |
| protected

Copy constructor.

Stable:
  ICU 2.4

## ◆ ~Transliterator()

virtual icu::Transliterator::~Transliterator | ( |  | ) |
| virtual

Destructor.

Stable:
  ICU 2.0

## Member Function Documentation

## ◆ _countAvailableSources()

static int32_t icu::Transliterator::_countAvailableSources | ( | void |  | ) |
| staticprotected

Non-mutexed internal method.

Internal:
  Do not use.

This API is for internal use only.

## ◆ _countAvailableTargets()

static int32_t icu::Transliterator::_countAvailableTargets | ( | const UnicodeString & | source | ) |
| staticprotected

Non-mutexed internal method.

Internal:
  Do not use.

This API is for internal use only.

## ◆ _countAvailableVariants()

static int32_t icu::Transliterator::_countAvailableVariants | ( | const UnicodeString & | source,
|  | const UnicodeString & | target
| ) |  |
| staticprotected

Non-mutexed internal method.

Internal:
  Do not use.

This API is for internal use only.

## ◆ _getAvailableSource()

static UnicodeString& icu::Transliterator::_getAvailableSource | ( | int32_t | index,
|  | UnicodeString & | result
| ) |  |
| staticprotected

Non-mutexed internal method.

Internal:
  Do not use.

This API is for internal use only.

## ◆ _getAvailableTarget()

static UnicodeString& icu::Transliterator::_getAvailableTarget | ( | int32_t | index,
|  | const UnicodeString & | source,
|  | UnicodeString & | result
| ) |  |
| staticprotected

Non-mutexed internal method.

Internal:
  Do not use.

This API is for internal use only.

## ◆ _getAvailableVariant()

static UnicodeString& icu::Transliterator::_getAvailableVariant | ( | int32_t | index,
|  | const UnicodeString & | source,
|  | const UnicodeString & | target,
|  | UnicodeString & | result
| ) |  |
| staticprotected

Non-mutexed internal method.

Internal:
  Do not use.

This API is for internal use only.

## ◆ _registerAlias()

static void icu::Transliterator::_registerAlias | ( | const UnicodeString & | aliasID,
|  | const UnicodeString & | realID
| ) |  |
| staticprotected

Internal:
  Do not use.

This API is for internal use only.

## ◆ _registerFactory()

static void icu::Transliterator::_registerFactory | ( | const UnicodeString & | id,
|  | Factory | factory,
|  | Token | context
| ) |  |
| staticprotected

Parameters

  id | the ID being registered
  factory | a function pointer that will be copied and called later when the given ID is passed to createInstance()
  context | a context pointer that will be stored and later passed to the factory function when an ID matching the registration ID is being instantiated with this factory.

Internal:
  Do not use. This API is for internal use only.

## ◆ _registerInstance()

static void icu::Transliterator::_registerInstance | ( | Transliterator * | adoptedObj | ) |
| staticprotected

Internal:
  Do not use.

This API is for internal use only.

## ◆ _registerSpecialInverse()

static void icu::Transliterator::_registerSpecialInverse | ( | const UnicodeString & | target,
|  | const UnicodeString & | inverseTarget,
|  | UBool | bidirectional
| ) |  |
| staticprotected

Register two targets as being inverses of one another.

For example, calling registerSpecialInverse("NFC", "NFD", true) causes Transliterator to form the following inverse relationships:

    NFC => NFD
    Any-NFC => Any-NFD
    NFD => NFC
    Any-NFD => Any-NFC

(Without the special inverse registration, the inverse of NFC would be NFC-Any.) Note that NFD is shorthand for Any-NFD, but that the presence or absence of "Any-" is preserved.

The relationship is symmetrical; registering (a, b) is equivalent to registering (b, a).

The relevant IDs must still be registered separately as factories or classes.

Only the targets are specified. Special inverses always have the form Any-Target1 <=> Any-Target2. The target should have canonical casing (the casing desired to be produced when an inverse is formed) and should contain no whitespace or other extraneous characters.

Parameters

  target | the target against which to register the inverse
  inverseTarget | the inverse of target, that is Any-target.getInverse() => Any-inverseTarget
  bidirectional | if true, register the reverse relation as well, that is, Any-inverseTarget.getInverse() => Any-target

Internal:
  Do not use. This API is for internal use only.

## ◆ adoptFilter()

void icu::Transliterator::adoptFilter | ( | UnicodeFilter * | adoptedFilter | ) |

Changes the filter used by this transliterator.

If the filter is set to `null` then no filtering will occur.

Callers must take care if a transliterator is in use by multiple threads. The filter should not be changed by one thread while another thread may be transliterating.

Parameters

  adoptedFilter | the new filter to be adopted.

Stable:
  ICU 2.0

## ◆ clone()

virtual Transliterator* icu::Transliterator::clone | ( |  | ) | const
| virtual

Implements Cloneable.

All subclasses are encouraged to implement this method if it is possible and reasonable to do so. Subclasses that are to be registered with the system using `registerInstance()` are required to implement this method. If a subclass does not implement clone() properly and is registered with the system using registerInstance(), then the default clone() implementation will return null, and calls to createInstance() will fail.

Returns
  a copy of the object.

See also
  registerInstance

Stable:
  ICU 2.0

## ◆ countAvailableIDs()

static int32_t icu::Transliterator::countAvailableIDs | ( | void |  | ) |
| static

Return the number of IDs currently registered with the system.

To retrieve the actual IDs, call getAvailableID(i) with i from 0 to countAvailableIDs() - 1.

Returns
  the number of IDs currently registered with the system.

Obsolete:
  ICU 3.4 use getAvailableIDs() instead

## ◆ countAvailableSources()

static int32_t icu::Transliterator::countAvailableSources | ( | void |  | ) |
| static

Return the number of registered source specifiers.

Returns
  the number of registered source specifiers.

Stable:
  ICU 2.0

## ◆ countAvailableTargets()

static int32_t icu::Transliterator::countAvailableTargets | ( | const UnicodeString & | source | ) |
| static

Return the number of registered target specifiers for a given source specifier.

Parameters

  source | the given source specifier.

Returns
  the number of registered target specifiers for a given source specifier.

Stable:
  ICU 2.0

## ◆ countAvailableVariants()

static int32_t icu::Transliterator::countAvailableVariants | ( | const UnicodeString & | source,
|  | const UnicodeString & | target
| ) |  |
| static

Return the number of registered variant specifiers for a given source-target pair.

Parameters

  source | the source specifiers.
  target | the target specifiers.

Stable:
  ICU 2.0

## ◆ countElements()

int32_t icu::Transliterator::countElements | ( |  | ) | const

Return the number of elements that make up this transliterator.

For example, if the transliterator "NFD;Jamo-Latin;Latin-Greek" were created, the return value of this method would be 3.

If this transliterator is not composed of other transliterators, then this method returns 1.

Returns
  the number of transliterators that compose this transliterator, or 1 if this transliterator is not composed of multiple transliterators

Stable:
  ICU 3.0

## ◆ createBasicInstance()

static Transliterator* icu::Transliterator::createBasicInstance | ( | const UnicodeString & | id,
|  | const UnicodeString * | canon
| ) |  |
| staticprotected

Create a transliterator from a basic ID.

This is an ID containing only the forward direction source, target, and variant.

Parameters

  id | a basic ID of the form S-T or S-T/V.
  canon | canonical ID to assign to the object, or NULL to leave the ID unchanged

Returns
  a newly created Transliterator or null if the ID is invalid.

Stable:
  ICU 2.4

## ◆ createFromRules()

static Transliterator* icu::Transliterator::createFromRules | ( | const UnicodeString & | ID,
|  | const UnicodeString & | rules,
|  | UTransDirection | dir,
|  | UParseError & | parseError,
|  | UErrorCode & | status
| ) |  |
| static

Returns a `Transliterator` object constructed from the given rule string.

This will be a rule-based Transliterator, if the rule string contains only rules, or a compound Transliterator, if it contains ID blocks, or a null Transliterator, if it contains ID blocks which parse as empty for the given direction.

Parameters

  ID | the id for the transliterator.
  rules | rules, separated by ';'
  dir | either FORWARD or REVERSE.
  parseError | Struct to receive information on position of error if an error is encountered
  status | Output param set to success/failure code.

Returns
  a newly created Transliterator

Stable:
  ICU 2.0

## ◆ createInstance() [1/2]

static Transliterator* icu::Transliterator::createInstance | ( | const UnicodeString & | ID,
|  | UTransDirection | dir,
|  | UErrorCode & | status
| ) |  |
| static

Returns a `Transliterator` object given its ID.

The ID must be either a system transliterator ID or a ID registered using `registerInstance()`.

Parameters

  ID | a valid ID, as enumerated by `getAvailableIDs()`
  dir | either FORWARD or REVERSE.
  status | Output param to filled in with a success or an error.

Returns
  A `Transliterator` object with the given ID

Stable:
  ICU 2.0

## ◆ createInstance() [2/2]

static Transliterator* icu::Transliterator::createInstance | ( | const UnicodeString & | ID,
|  | UTransDirection | dir,
|  | UParseError & | parseError,
|  | UErrorCode & | status
| ) |  |
| static

Returns a `Transliterator` object given its ID.

The ID must be either a system transliterator ID or a ID registered using `registerInstance()`.

Parameters

  ID | a valid ID, as enumerated by `getAvailableIDs()`
  dir | either FORWARD or REVERSE.
  parseError | Struct to recieve information on position of error if an error is encountered
  status | Output param to filled in with a success or an error.

Returns
  A `Transliterator` object with the given ID

See also
  registerInstance
  getAvailableIDs
  getID

Stable:
  ICU 2.0

## ◆ createInverse()

Transliterator* icu::Transliterator::createInverse | ( | UErrorCode & | status | ) | const

Returns this transliterator's inverse.

See the class documentation for details. This implementation simply inverts the two entities in the ID and attempts to retrieve the resulting transliterator. That is, if `getID()` returns "A-B", then this method will return the result of `createInstance("B-A")`, or `null` if that call fails.

Subclasses with knowledge of their inverse may wish to override this method.

Parameters

  status | Output param to filled in with a success or an error.

Returns
  a transliterator that is an inverse, not necessarily exact, of this transliterator, or `null` if no such transliterator is registered.

See also
  registerInstance

Stable:
  ICU 2.0

## ◆ filteredTransliterate()

virtual void icu::Transliterator::filteredTransliterate | ( | Replaceable & | text,
|  | UTransPosition & | index,
|  | UBool | incremental
| ) |  | const
| virtual

Transliterate a substring of text, as specified by index, taking filters into account.

This method is for subclasses that need to delegate to another transliterator.

Parameters

  text | the text to be transliterated
  index | the position indices
  incremental | if true, then assume more characters may be inserted at index.limit, and postpone processing to accommodate future incoming characters

Stable:
  ICU 2.4

## ◆ finishTransliteration()

virtual void icu::Transliterator::finishTransliteration | ( | Replaceable & | text,
|  | UTransPosition & | index
| ) |  | const
| virtual

Finishes any pending transliterations that were waiting for more characters.

Clients should call this method as the last call after a sequence of one or more calls to `transliterate()`.

Parameters

  text | the buffer holding transliterated and untransliterated text.
  index | the array of indices previously passed to transliterate

Stable:
  ICU 2.0

## ◆ getAvailableID()

static const UnicodeString& icu::Transliterator::getAvailableID | ( | int32_t | index | ) |
| static

Return the index-th available ID.

index must be between 0 and countAvailableIDs() - 1, inclusive. If index is out of range, the result of getAvailableID(0) is returned.

Parameters

  index | the given ID index.

Returns
  the index-th available ID. index must be between 0 and countAvailableIDs() - 1, inclusive. If index is out of range, the result of getAvailableID(0) is returned.

Obsolete:
  ICU 3.4 use getAvailableIDs() instead; this function is not thread safe, since it returns a reference to storage that may become invalid if another thread calls unregister

## ◆ getAvailableIDs()

static StringEnumeration* icu::Transliterator::getAvailableIDs | ( | UErrorCode & | ec | ) |
| static

Return a StringEnumeration over the IDs available at the time of the call, including user-registered IDs.

Parameters

  ec | input-output error code

Returns
  a newly-created StringEnumeration over the transliterators available at the time of the call. The caller should delete this object when done using it.

Stable:
  ICU 3.0

## ◆ getAvailableSource()

static UnicodeString& icu::Transliterator::getAvailableSource | ( | int32_t | index,
|  | UnicodeString & | result
| ) |  |
| static

Return a registered source specifier.

Parameters

  index | which specifier to return, from 0 to n-1, where n = countAvailableSources()
  result | fill-in paramter to receive the source specifier. If index is out of range, result will be empty.

Returns
  reference to result

Stable:
  ICU 2.0

## ◆ getAvailableTarget()

static UnicodeString& icu::Transliterator::getAvailableTarget | ( | int32_t | index,
|  | const UnicodeString & | source,
|  | UnicodeString & | result
| ) |  |
| static

Return a registered target specifier for a given source.

Parameters

  index | which specifier to return, from 0 to n-1, where n = countAvailableTargets(source)
  source | the source specifier
  result | fill-in paramter to receive the target specifier. If source is invalid or if index is out of range, result will be empty.

Returns
  reference to result

Stable:
  ICU 2.0

## ◆ getAvailableVariant()

static UnicodeString& icu::Transliterator::getAvailableVariant | ( | int32_t | index,
|  | const UnicodeString & | source,
|  | const UnicodeString & | target,
|  | UnicodeString & | result
| ) |  |
| static

Return a registered variant specifier for a given source-target pair.

Parameters

  index | which specifier to return, from 0 to n-1, where n = countAvailableVariants(source, target)
  source | the source specifier
  target | the target specifier
  result | fill-in paramter to receive the variant specifier. If source is invalid or if target is invalid or if index is out of range, result will be empty.

Returns
  reference to result

Stable:
  ICU 2.0

## ◆ getDisplayName() [1/2]

static UnicodeString& icu::Transliterator::getDisplayName | ( | const UnicodeString & | ID,
|  | const Locale & | inLocale,
|  | UnicodeString & | result
| ) |  |
| static

Returns a name for this transliterator that is appropriate for display to the user in the given locale.

This name is taken from the locale resource data in the standard manner of the `java.text` package.

If no localized names exist in the system resource bundles, a name is synthesized using a localized `MessageFormat` pattern from the resource data. The arguments to this pattern are an integer followed by one or two strings. The integer is the number of strings, either 1 or 2. The strings are formed by splitting the ID for this transliterator at the first '-'. If there is no '-', then the entire ID forms the only string.

Parameters

  ID | the string identifier for this transliterator
  inLocale | the Locale in which the display name should be localized.
  result | Output param to receive the display name

Returns
  A reference to 'result'.

Stable:
  ICU 2.0

## ◆ getDisplayName() [2/2]

static UnicodeString& icu::Transliterator::getDisplayName | ( | const UnicodeString & | ID,
|  | UnicodeString & | result
| ) |  |
| static

Returns a name for this transliterator that is appropriate for display to the user in the default locale.

See getDisplayName for details.

Parameters

  ID | the string identifier for this transliterator
  result | Output param to receive the display name

Returns
  A reference to 'result'.

Stable:
  ICU 2.0

## ◆ getDynamicClassID()

virtual UClassID icu::Transliterator::getDynamicClassID | ( | void |  | ) | const
| pure virtual

Returns a unique class ID polymorphically.

This method is to implement a simple version of RTTI, since not all C++ compilers support genuine RTTI. Polymorphic operator==() and clone() methods call this method.

Concrete subclasses of Transliterator must use the UOBJECT_DEFINE_RTTI_IMPLEMENTATION macro from uobject.h to provide the RTTI functions.

Returns
  The class ID for this object. All objects of a given class have the same class ID. Objects of other classes have different class IDs.

Stable:
  ICU 2.0

Reimplemented from icu::UObject.

## ◆ getElement()

const Transliterator& icu::Transliterator::getElement | ( | int32_t | index,
|  | UErrorCode & | ec
| ) |  | const

Return an element that makes up this transliterator.

For example, if the transliterator "NFD;Jamo-Latin;Latin-Greek" were created, the return value of this method would be one of the three transliterator objects that make up that transliterator: [NFD, Jamo-Latin, Latin-Greek].

If this transliterator is not composed of other transliterators, then this method will return a reference to this transliterator when given the index 0.

Parameters

  index | a value from 0..countElements()-1 indicating the transliterator to return
  ec | input-output error code

Returns
  one of the transliterators that makes up this transliterator, if this transliterator is made up of multiple transliterators, otherwise a reference to this object if given an index of 0

Stable:
  ICU 3.0

## ◆ getFilter()

const UnicodeFilter* icu::Transliterator::getFilter | ( | void |  | ) | const

Returns the filter used by this transliterator, or `NULL` if this transliterator uses no filter.

Returns
  the filter used by this transliterator, or `NULL` if this transliterator uses no filter.

Stable:
  ICU 2.0

## ◆ getID()

virtual const UnicodeString& icu::Transliterator::getID | ( | void |  | ) | const
| virtual

Returns a programmatic identifier for this transliterator.

If this identifier is passed to `createInstance()`, it will return this object, if it has been registered.

Returns
  a programmatic identifier for this transliterator.

See also
  registerInstance
  registerFactory
  getAvailableIDs

Stable:
  ICU 2.0

## ◆ getMaximumContextLength()

int32_t icu::Transliterator::getMaximumContextLength | ( | void |  | ) | const
| inline

Returns the length of the longest context required by this transliterator.

This is preceding context. The default implementation supplied by `Transliterator` returns zero; subclasses that use preceding context should override this method to return the correct value. For example, if a transliterator translates "ddd" (where d is any digit) to "555" when preceded by "(ddd)", then the preceding context length is 5, the length of "(ddd)".

Returns
  The maximum number of preceding context characters this transliterator needs to examine

Stable:
  ICU 2.0

Definition at line 1562 of file translit.h.

## ◆ getSourceSet()

UnicodeSet& icu::Transliterator::getSourceSet | ( | UnicodeSet & | result | ) | const

Returns the set of all characters that may be modified in the input text by this Transliterator.

This incorporates this object's current filter; if the filter is changed, the return value of this function will change. The default implementation returns an empty set. Some subclasses may override handleGetSourceSet to return a more precise result. The return result is approximate in any case and is intended for use by tests, tools, or utilities.

Parameters

  result | receives result set; previous contents lost

Returns
  a reference to result

See also
  getTargetSet
  handleGetSourceSet

Stable:
  ICU 2.4

## ◆ getStaticClassID()

static UClassID icu::Transliterator::getStaticClassID | ( | void |  | ) |
| static

Return the class ID for this class.

This is useful only for comparing to a return value from getDynamicClassID(). Note that Transliterator is an abstract base class, and therefor no fully constructed object will have a dynamic UCLassID that equals the UClassID returned from TRansliterator::getStaticClassID().

Returns
  The class ID for class Transliterator.

Stable:
  ICU 2.0

## ◆ getTargetSet()

virtual UnicodeSet& icu::Transliterator::getTargetSet | ( | UnicodeSet & | result | ) | const
| virtual

Returns the set of all characters that may be generated as replacement text by this transliterator.

The default implementation returns the empty set. Some subclasses may override this method to return a more precise result. The return result is approximate in any case and is intended for use by tests, tools, or utilities requiring such meta-information.

Parameters

  result | receives result set; previous contents lost

Returns
  a reference to result

See also
  getTargetSet

Stable:
  ICU 2.4

## ◆ handleGetSourceSet()

virtual void icu::Transliterator::handleGetSourceSet | ( | UnicodeSet & | result | ) | const
| virtual

Framework method that returns the set of all characters that may be modified in the input text by this Transliterator, ignoring the effect of this object's filter.

The base class implementation returns the empty set. Subclasses that wish to implement this should override this method.

Returns
  the set of characters that this transliterator may modify. The set may be modified, so subclasses should return a newly-created object.

Parameters

  result | receives result set; previous contents lost

See also
  getSourceSet
  getTargetSet

Stable:
  ICU 2.4

## ◆ handleTransliterate()

virtual void icu::Transliterator::handleTransliterate | ( | Replaceable & | text,
|  | UTransPosition & | pos,
|  | UBool | incremental
| ) |  | const
| protectedpure virtual

Abstract method that concrete subclasses define to implement their transliteration algorithm.

This method handles both incremental and non-incremental transliteration. Let `originalStart` refer to the value of `pos.start` upon entry.

- If `incremental` is false, then this method should transliterate all characters between `pos.start` and `pos.limit`. Upon return `pos.start` must == `pos.limit`.

- If `incremental` is true, then this method should transliterate all characters between `pos.start` and `pos.limit` that can be unambiguously transliterated, regardless of future insertions of text at `pos.limit`. Upon return, `pos.start` should be in the range [`originalStart`, `pos.limit`). `pos.start` should be positioned such that characters [`originalStart`, `pos.start`) will not be changed in the future by this transliterator and characters [`pos.start`, `pos.limit`) are unchanged.

Implementations of this method should also obey the following invariants:

- `pos.limit` and `pos.contextLimit` should be updated to reflect changes in length of the text between `pos.start` and `pos.limit`. The difference `pos.contextLimit - pos.limit` should not change.

- `pos.contextStart` should not change.

- Upon return, neither `pos.start` nor `pos.limit` should be less than `originalStart`.

- Text before `originalStart` and text after `pos.limit` should not change.

- Text before `pos.contextStart` and text after `pos.contextLimit` should be ignored.

Subclasses may safely assume that all characters in [`pos.start`, `pos.limit`) are filtered. In other words, the filter has already been applied by the time this method is called. See `filteredTransliterate()`.

This method is not for public consumption. Calling this method directly will transliterate [`pos.start`, `pos.limit`) without applying the filter. End user code should call `transliterate()` instead of this method. Subclass code and wrapping transliterators should call `filteredTransliterate()` instead of this method.

Parameters

  text | the buffer holding transliterated and untransliterated text
  pos | the indices indicating the start, limit, context start, and context limit of the text.
  incremental | if true, assume more text may be inserted at `pos.limit` and act accordingly. Otherwise, transliterate all text between `pos.start` and `pos.limit` and move `pos.start` up to `pos.limit`.

See also
  transliterate

Stable:
  ICU 2.4

## ◆ integerToken()

Transliterator::Token icu::Transliterator::integerToken | ( | int32_t | i | ) |
| inlinestatic

Return a token containing an integer.

Returns
  a token containing an integer.

Internal:
  Do not use. This API is for internal use only.

Definition at line 1574 of file translit.h.

References icu::Transliterator::Token::integer.

## ◆ operator=()

Transliterator& icu::Transliterator::operator= | ( | const Transliterator & |  | ) |
| protected

Assignment operator.

Stable:
  ICU 2.4

## ◆ orphanFilter()

UnicodeFilter* icu::Transliterator::orphanFilter | ( | void |  | ) |

Returns the filter used by this transliterator, or `NULL` if this transliterator uses no filter.

The caller must eventually delete the result. After this call, this transliterator's filter is set to `NULL`.

Returns
  the filter used by this transliterator, or `NULL` if this transliterator uses no filter.

Stable:
  ICU 2.4

## ◆ pointerToken()

Transliterator::Token icu::Transliterator::pointerToken | ( | void * | p | ) |
| inlinestatic

Return a token containing a pointer.

Returns
  a token containing a pointer.

Internal:
  Do not use. This API is for internal use only.

Definition at line 1580 of file translit.h.

References icu::Transliterator::Token::pointer.

## ◆ registerAlias()

static void icu::Transliterator::registerAlias | ( | const UnicodeString & | aliasID,
|  | const UnicodeString & | realID
| ) |  |
| static

Registers an ID string as an alias of another ID string.

That is, after calling this function, `createInstance(aliasID)` will return the same thing as `createInstance(realID)`. This is generally used to create shorter, more mnemonic aliases for long compound IDs.

Parameters

  aliasID | The new ID being registered.
  realID | The ID that the new ID is to be an alias for. This can be a compound ID and can include filters and should refer to transliterators that have already been registered with the framework, although this isn't checked.

Stable:
  ICU 3.6

## ◆ registerFactory()

static void icu::Transliterator::registerFactory | ( | const UnicodeString & | id,
|  | Factory | factory,
|  | Token | context
| ) |  |
| static

Registers a factory function that creates transliterators of a given ID.

Because ICU may choose to cache Transliterators internally, this must be called at application startup, prior to any calls to Transliterator::createXXX to avoid undefined behavior.

Parameters

  id | the ID being registered
  factory | a function pointer that will be copied and called later when the given ID is passed to createInstance()
  context | a context pointer that will be stored and later passed to the factory function when an ID matching the registration ID is being instantiated with this factory.

Stable:
  ICU 2.0

## ◆ registerInstance()

static void icu::Transliterator::registerInstance | ( | Transliterator * | adoptedObj | ) |
| static

Registers an instance `obj` of a subclass of `Transliterator` with the system.

When `createInstance()` is called with an ID string that is equal to `obj->getID()`, then `obj->clone()` is returned.

After this call the Transliterator class owns the adoptedObj and will delete it.

Because ICU may choose to cache Transliterators internally, this must be called at application startup, prior to any calls to Transliterator::createXXX to avoid undefined behavior.

Parameters

  adoptedObj | an instance of subclass of `Transliterator` that defines `clone()`

See also
  createInstance
  registerFactory
  unregister

Stable:
  ICU 2.0

## ◆ setID()

void icu::Transliterator::setID | ( | const UnicodeString & | id | ) |
| inlineprotected

Set the ID of this transliterators.

Subclasses shouldn't do this, unless the underlying script behavior has changed.

Parameters

  id | the new id t to be set.

Stable:
  ICU 2.4

Definition at line 1566 of file translit.h.

References icu::UnicodeString::append(), and icu::UnicodeString::truncate().

## ◆ setMaximumContextLength()

void icu::Transliterator::setMaximumContextLength | ( | int32_t | maxContextLength | ) |
| protected

Method for subclasses to use to set the maximum context length.

Parameters

  maxContextLength | the new value to be set.

See also
  getMaximumContextLength

Stable:
  ICU 2.4

## ◆ toRules()

virtual UnicodeString& icu::Transliterator::toRules | ( | UnicodeString & | result,
|  | UBool | escapeUnprintable
| ) |  | const
| virtual

Create a rule string that can be passed to createFromRules() to recreate this transliterator.

Parameters

  result | the string to receive the rules. Previous contents will be deleted.
  escapeUnprintable | if true then convert unprintable character to their hex escape representations, \uxxxx or \Uxxxxxxxx. Unprintable characters are those other than U+000A, U+0020..U+007E.

Stable:
  ICU 2.0

## ◆ transliterate() [1/5]

virtual void icu::Transliterator::transliterate | ( | Replaceable & | text | ) | const
| virtual

Transliterates an entire string in place.

Convenience method.

Parameters

  text | the string to be transliterated

Stable:
  ICU 2.0

## ◆ transliterate() [2/5]

virtual int32_t icu::Transliterator::transliterate | ( | Replaceable & | text,
|  | int32_t | start,
|  | int32_t | limit
| ) |  | const
| virtual

Transliterates a segment of a string, with optional filtering.

Parameters

  text | the string to be transliterated
  start | the beginning index, inclusive; `0 <= start <= limit`.
  limit | the ending index, exclusive; `start <= limit <= text.length()`.

Returns
  The new limit index. The text previously occupying `[start, limit)` has been transliterated, possibly to a string of a different length, at `[start,` new-limit`)`, where new-limit is the return value. If the input offsets are out of bounds, the returned value is -1 and the input string remains unchanged.

Stable:
  ICU 2.0

## ◆ transliterate() [3/5]

virtual void icu::Transliterator::transliterate | ( | Replaceable & | text,
|  | UTransPosition & | index,
|  | const UnicodeString & | insertion,
|  | UErrorCode & | status
| ) |  | const
| virtual

Transliterates the portion of the text buffer that can be transliterated unambiguosly after new text has been inserted, typically as a result of a keyboard event.

The new text in `insertion` will be inserted into `text` at `index.limit`, advancing `index.limit` by `insertion.length()`. Then the transliterator will try to transliterate characters of `text` between `index.cursor` and `index.limit`. Characters before `index.cursor` will not be changed.

Upon return, values in `index` will be updated. `index.start` will be advanced to the first character that future calls to this method will read. `index.cursor` and `index.limit` will be adjusted to delimit the range of text that future calls to this method may change.

Typical usage of this method begins with an initial call with `index.start` and `index.limit` set to indicate the portion of `text` to be transliterated, and `index.cursor == index.start`. Thereafter, `index` can be used without modification in future calls, provided that all changes to `text` are made via this method.

This method assumes that future calls may be made that will insert new text into the buffer. As a result, it only performs unambiguous transliterations. After the last call to this method, there may be untransliterated text that is waiting for more input to resolve an ambiguity. In order to perform these pending transliterations, clients should call finishTransliteration after the last call to this method has been made.

Parameters

  text | the buffer holding transliterated and untransliterated text
  index | an array of three integers.

- `index.start`: the beginning index, inclusive; `0 <= index.start <= index.limit`.

- `index.limit`: the ending index, exclusive; `index.start <= index.limit <= text.length()`. `insertion` is inserted at `index.limit`.

- `index.cursor`: the next character to be considered for transliteration; `index.start <= index.cursor <= index.limit`. Characters before `index.cursor` will not be changed by future calls to this method.

Parameters

  insertion | text to be inserted and possibly transliterated into the translation buffer at `index.limit`. If `null` then no text is inserted.
  status | Output param to filled in with a success or an error.

See also
  handleTransliterate

Exceptions

  IllegalArgumentException | if `index` is invalid

See also
  UTransPosition

Stable:
  ICU 2.0

## ◆ transliterate() [4/5]

virtual void icu::Transliterator::transliterate | ( | Replaceable & | text,
|  | UTransPosition & | index,
|  | UChar32 | insertion,
|  | UErrorCode & | status
| ) |  | const
| virtual

Transliterates the portion of the text buffer that can be transliterated unambiguosly after a new character has been inserted, typically as a result of a keyboard event.

This is a convenience method.

Parameters

  text | the buffer holding transliterated and untransliterated text
  index | an array of three integers.
  insertion | text to be inserted and possibly transliterated into the translation buffer at `index.limit`.
  status | Output param to filled in with a success or an error.

See also
  transliterate(Replaceable&, UTransPosition&, const UnicodeString&, UErrorCode&) const

Stable:
  ICU 2.0

## ◆ transliterate() [5/5]

virtual void icu::Transliterator::transliterate | ( | Replaceable & | text,
|  | UTransPosition & | index,
|  | UErrorCode & | status
| ) |  | const
| virtual

Transliterates the portion of the text buffer that can be transliterated unambiguosly.

This is a convenience method; see transliterate(Replaceable&, UTransPosition&, const UnicodeString&, UErrorCode&) const for details.

Parameters

  text | the buffer holding transliterated and untransliterated text
  index | an array of three integers.
  status | Output param to filled in with a success or an error.

See also
  transliterate(Replaceable&, UTransPosition&, const UnicodeString&, UErrorCode &) const

Stable:
  ICU 2.0

## ◆ unregister()

static void icu::Transliterator::unregister | ( | const UnicodeString & | ID | ) |
| static

Unregisters a transliterator or class.

This may be either a system transliterator or a user transliterator or class. Any attempt to construct an unregistered transliterator based on its ID will fail.

Because ICU may choose to cache Transliterators internally, this should be called during application shutdown, after all calls to Transliterator::createXXX to avoid undefined behavior.

Parameters

  ID | the ID of the transliterator or class

Returns
  the `Object` that was registered with `ID`, or `null` if none was

See also
  registerInstance
  registerFactory

Stable:
  ICU 2.0

The documentation for this class was generated from the following file:

- translit.h